Holographic optical device, camera finder indication, and camera

ABSTRACT

The present invention relates to a holographic optical element, a viewfinder display of a camera using thereof, and a camera. The purpose of the present invention is to show various superimposed displays for various information with securing a bright viewfinder image. In the holographic optical element according to the present invention, a liquid crystal ( 13 ) whose orientation is changeable and a liquid crystal ( 14 ) whose orientation is fixed are arranged alternately with a striped shape between the transparent members ( 12   a ) ( 12   b ) on which the transparent electrodes ( 11   a ) ( 11   b ) are formed facing with each other.

TECHNICAL FIELD

The present invention relates to a holographic optical element, aviewfinder display of a camera, and a camera.

BACKGROUND ART

It has been known a viewfinder display that shows various informationsuch as a focus detection area and the like in a viewfinder of a cameratogether with an object image, which is a so-called superimposeddisplay. As a viewfinder display of this kind, a transparent type liquidcrystal display or a high polymer dispersion type liquid crystal displaycapable of displaying various information arranged in the vicinity of ascreen has been proposed in such as Japanese Patent ApplicationLaid-Open Nos. 4-324844 and 10-48592. Moreover, in Japanese PatentApplication Laid-Open No. 7-319032, it has been proposed a constructionthat a light projection system such as a light-emitting diode projectslight to a micro-prism locating in the vicinity of a screen and variousinformation can be displayed by the reflected light.

However, in the viewfinder display using a transparent type liquidcrystal display, since the transmittance of the transparent type liquidcrystal display is low, it becomes difficult to observe the image of theviewfinder (various information as well as the object image). Moreover,in the viewfinder using a high polymer dispersion type liquid crystaldisplay, although the transmittance of the high polymer dispersion typeliquid crystal display is high, light is diffused upon applyingno-voltage, so that it becomes a restriction on a viewfinder display.Furthermore, in the above-described viewfinder using a micro-prism, itis difficult to show various information with a fine display.

DISCLOSURE OF THE INVENTION

The present invention is made in view of the aforementioned problems andhas an object to provide a holographic optical element, a viewfinderdisplay of a camera, and a camera that makes it possible to show varioussuperimposed displays for various information with securing a brightviewfinder image.

In order to solve the aforementioned problems, the present inventionprovides a holographic optical element which includes a pair ofboard-shaped transparent members arranged with a distance facing witheach other, transparent electrodes formed on the respective transparentmembers and facing with each other, a liquid crystal whose orientationis changeable, and a liquid crystal whose orientation is fixed. Theorientation changeable liquid crystal and the orientation-fixed liquidcrystal are arranged alternately with a striped shape between thetransparent members on which the transparent electrodes are formedfacing with each other.

In the holographic optical element of the present invention, it ispreferable that the orientation-fixed liquid crystal is anultraviolet-setting liquid crystal.

In the holographic optical element of the present invention, it ispreferable that the holographic optical element diffracts light uponapplying no-voltage since the orientation of the liquid crystal and theorientation of the orientation-fixed liquid crystal are different uponapplying no-voltage, and upon applying voltage, the orientation of theliquid crystal varies so that the orientation of the liquid crystal andthe orientation of the orientation-fixed liquid crystal become the same.

In the holographic optical element of the present invention, it ispreferable that the holographic optical element diffracts light uponapplying voltage since the orientation of the liquid crystal and theorientation of the orientation-fixed liquid crystal are different uponapplying voltage, and upon applying no-voltage, the orientation of theliquid crystal varies so that the orientation of the liquid crystal andthe orientation of the orientation-fixed liquid crystal become the same.

The present invention provides a viewfinder display of a cameradisplaying given information together with an object image withsuperimposed manner, the viewfinder display uses the aforementionedholographic optical element.

In the viewfinder display of a camera of the present invention, it ispreferable that the transparent electrodes are arranged on thetransparent members such that the transparent electrodes form a figureshape and a letter shape, and the figure and the letter are displayed asthe given information.

In the viewfinder display of a camera of the present invention, it ispreferable that the transparent electrodes are arranged on thetransparent members such that the given information is displayed as adot-matrix.

In the viewfinder display of a camera of the present inventiondisplaying given information together with an object image withsuperimposed manner, it is preferable that the viewfinder display usingin combination with a plurality of holographic optical elementsaccording to the present invention.

The present invention provides a camera arranging the viewfinder displayof a camera according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a single-lens-reflex cameraaccording to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a holographic optical elementaccording to the first embodiment of the present invention.

FIGS. 3A and 3B are diagrams respectively showing a transparentelectrode for the holographic optical element according to the firstembodiment of the present invention and an example of informationdisplayed in the viewfinder.

FIGS. 4A and 4B are diagrams explaining operation principles of theholographic optical element according to the first embodiment of thepresent invention upon applying no-voltage and upon applying voltage,respectively.

FIG. 5 is a diagram showing another example of the holographic opticalelement.

FIGS. 6A and 6B are diagrams explaining a fabrication method of theholographic optical element according to the first embodiment of thepresent invention.

FIGS. 7A and 7B are schematic diagrams showing a device for fabricatingthe holographic optical element with another fabrication method and anenlarged drawing of a cell portion of FIG. 7A showing wave fronts ofbundles of rays, respectively.

FIG. 8 is a schematic view showing a viewfinder display for a compactcamera according to a second embodiment of the present invention.

FIGS. 9A and 9B are views respectively showing transparent electrodes ofa holographic optical element and an example of information displayed inthe field of the viewfinder according to the second embodiment of thepresent invention.

EMBODIMENT OF THE INVENTION

Each embodiment of the present invention is explained below withreference to accompanying drawings.

First Embodiment

A single-lens-reflex camera equipped with a viewfinder display using aholographic optical element according to a first embodiment of thepresent invention is explained.

At first, construction and operation of the single-lens-reflex cameraaccording to the first embodiment of the present invention is explained.FIG. 1 is a schematic diagram showing a single-lens-reflex cameraaccording to a first embodiment of the present invention. In FIG. 1, asingle-lens-reflex camera 1 is equipped with a photographic lens 3removably attached to a camera body 2, a quick return mirror 4 forreflecting light from an object through the photographic lens 3, ascreen 5 locating in a position conjugate with a photosensitive surfaceof a photographic film (not shown), a pentagonal roof prism 6 and aneyepiece 7 for observing the object image formed on the screen 5.

In the camera body 2, a holographic optical element 8, which isexplained later, is locating in the vicinity of the screen 5. A lightsource 9 for illuminating the holographic optical element 8 is arrangednear a side of the holographic optical element 8. Moreover, a driver 10for electrically controlling the optical characteristic of theholographic optical element 8 is connected to the holographic opticalelement 8.

In a single-lens-reflex camera having the above-described construction,object light L1 from an object (not shown) passes through thephotographic lens 3 and is reflected by the quick return mirror 4 andforms an image on the screen 5. The light passing through the screen 5passes through the holographic optical element 8, is reflected by thepentagonal roof prism 6, and observed as an object image by aphotographer (a viewfinder observer) through the eyepiece 7.

Upon photographing the object, the quick return mirror 4 is removed fromthe optical path so that the object light L1 reaches the photographicfilm to expose the film (the object is photographed on the film).

Then, light emitted from the light source 9 is incident to theholographic optical element 8, and diffracted by the holographic opticalelement 8 in the direction of the pentagonal roof prism 6 (upward).Here, the holographic optical element 8 is controlled by the driver 10so as to display given information (various information such as a focusdetection area necessary for the photographer) in the field of theviewfinder. The diffraction and the construction of the holographicoptical element 8 are explained later in detail.

The diffracted light L2 is reflected by the pentagonal roof prism 6 andobserved as a given information by the photographer through the eyepiece7.

With the construction described above, the given information isdisplayed in the field of the viewfinder together with the object image(superimposed display), so that the photographer can observe the giveninformation and the object image at a time.

The holographic optical element 8 which is the characteristic portion ofthe first embodiment is explained in detail.

The construction of the holographic optical element 8 is explained withreference to FIG. 2. FIG. 2 is a sectional view showing a holographicoptical element according to the first embodiment of the presentinvention.

In the holographic optical element 8 shown in FIG. 2, transparentelectrodes 11 a and 11 b are applied on a pair of transparent glassplates 12 a and 12 b arranged with a distance facing with each other.These transparent electrodes 11 a and 11 b are arranged facing with eachother. In the present embodiment, these transparent electrodes 11 a and11 b have the same shape with each other, in other words, the shapescorrespond with each other upon seeing from upward in FIG. 2 (in FIG. 1,seen from the pentagonal roof prism 6 side) so as to shape a letter or afigure as shown in FIG. 3A to be arranged on each glass plate 12 a or 12b. FIG. 3A is a diagram showing a transparent electrode 11 a or 11 b forthe holographic optical element 8 according to the first embodiment ofthe present invention. With the shape of the transparent electrode 11 aor 11 b, the holographic optical element 8 makes it possible to displaya given information composed of figures and letters in the field of theviewfinder by diffracting the light from the light source 9.

The transparent electrodes 11 a and 11 b are connected to theabove-described driver 10 by wiring (not shown) and voltage can beapplied to these transparent electrodes 11 a and 11 b facing with eachother. Between the glass plates 12 a and 12 b equipped with thesetransparent electrodes 11 a and 11 b, a liquid crystal 13 and anorientation-fixed liquid crystal 14 are arranged alternately with astriped shape extending in the direction to the end of the holographicoptical element 8 (horizontal direction in FIG. 2). The liquid crystal13 changes orientation thereof by applying voltage/no-voltage. On theother hand, the orientation-fixed liquid crystal 14 is aultraviolet-setting liquid crystal which does not change orientationthereof regardless of applying voltage/no-voltage. In the state withoutapplying voltage, orientation of the liquid crystal 13 is aligned withthat of the ultraviolet-setting liquid crystal 14. Accordingly, byapplying voltage between the transparent electrodes 11 a and 11 b facingwith each other by means of the driver 10, the orientation of the liquidcrystal 13 locating between the transparent electrodes 11 a and 11 bchanges.

Moreover, the end portions of the holographic optical element 8 aresealed by a sealant 15.

Then, the operation principle of the holographic optical element 8 isexplained with reference to FIGS. 4A and 4B. FIGS. 4A and 4B arediagrams explaining operation principle of the holographic opticalelement according to the first embodiment of the present invention uponapplying no-voltage and upon applying voltage, respectively.

As shown in FIG. 4A, upon applying no-voltage between the transparentelectrodes 11 a and 11 b, orientation of the liquid crystal 13 is thesame as that of the ultraviolet-setting liquid crystal 14 and ishorizontal direction of FIG. 4A. Accordingly, refractive indices of theliquid crystal portion 13 and 14 of the holographic optical element 8become substantially equal. Therefore, since there is no difference inrefractive indices of the liquid crystal 13 and 14, the light emittedfrom the light source 9 and incident to the holographic optical element8 from a side, passes through the element 8 without being diffracted andcomes out from the opposite side of the incident side. Upon applyingno-voltage, the light from the light source 9 passes through theholographic optical element 8 in this manner. The transmitted light isnot led to the eyepiece 7, so that the photographer observes only theobject image through the eyepiece 7.

On the other hand, when applying the voltage between the transparentelectrodes 11 a and 11 b by the driver 10, the orientation of the liquidcrystal 13 changes to vertical direction in FIG. 4B. The orientation ofthe ultraviolet-setting liquid crystal 14 does not change from the stateupon applying no-voltage and is horizontal direction in FIG. 4B.Accordingly, in a liquid crystal portion 16 locating between thetransparent electrodes where voltage is applied by the driver 10 in theholographic optical element 8, a high refractive index portion(vertically oriented liquid crystal 13 in FIG. 4B) and a low refractiveindex portion (horizontally oriented ultraviolet-setting liquid crystal14 in FIG. 4B) are arranged alternately with a striped shape, in otherwords, refractive index of the liquid crystal portion 16 changes with astriped shape (in the shape of a diffraction grating). Accordingly, thelight emitted from the light source 9 and incident into the holographicoptical element 8 from a side is diffracted at the liquid crystalportion 16 in the direction satisfying Bragg's diffraction condition. Inthe present embodiment, Bragg's diffraction condition is set such thatthe light from the light source 9 is diffracted upward in the verticaldirection in FIG. 4B. Accordingly, the light passing through theholographic optical element 8 is diffracted upward in FIG. 4B (in thedirection of the pentagonal roof prism) and comes out from the exitsurface 8 a. Upon applying voltage, the light from the light source 9 isdiffracted by the holographic optical element 8 in this manner, and ledto the eyepiece 7 through the pentagonal roof prism 6. Accordingly, theholographic optical element 8 is controlled by applying voltage orno-voltage to each portion of the transparent electrode by means of thedriver 10, so that given information is displayed in various ways in thefield of the viewfinder superimposing the object image. In the firstembodiment, an example of information (focus detection area 17 a,exposure time 17 b, and f-number 17 c) displayed in the field of theviewfinder 17 is shown in FIG. 3B. FIG. 3B is a diagram showing anexample of information displayed in the field of the viewfinderaccording to the first embodiment of the present invention.

As described above, by equipping a holographic optical element composedof a liquid crystal and an orientation-fixed liquid crystal into theviewfinder display, a single-lens-reflex camera according to the firstembodiment of the present invention makes it possible to show varioussuperimposed displays for various information with securing a brightviewfinder image.

Variations of the holographic optical element 8 according to the firstembodiment are explained below.

The above-described holographic optical element 8 according to the firstembodiment diffracts basically monochromatic light. Accordingly, variousinformation is displayed in monochromatic light in the field of theviewfinder. In the present invention, construction of a holographicoptical element is not limited to this.

FIG. 5 is a diagram showing another example of the holographic opticalelement. A holographic optical element 18 shown in FIG. 5 is constructedby three kinds of holographic optical elements composed of a holographicoptical element 18R diffracting red light, a holographic optical element18B diffracting blue light in the same direction of the red light, and aholographic optical element 18G diffracting green light in the samedirection of the red light.

Such a holographic optical element 18 is installed in a viewfinderdisplay. The light source 9 illuminates each holographic optical element18R, 18G, and 18B with white light and the driver 10 applies voltage toeach holographic optical element 18R, 18G, and 18B in turn withtime-sharing. Accordingly, upon applying voltage, each holographicoptical element 18R, 18G, and 18B diffracts corresponding color of lightamong white light. Therefore, the holographic optical element 18 makesit possible to diffract each color of light superimposing manner in thesame direction.

As described above, the viewfinder display using the holographic opticalelement 18 makes it possible to display given information in colors inthe field of the viewfinder. In addition, given information can bedisplayed in the field of the viewfinder display in full color byarbitrarily changing diffraction efficiency of each holographic opticalelement 18R, 18G, and 18B.

In the holographic optical element 8 according to the first embodiment,transparent electrodes 11 a and 11 b formed on a pair of glass plates 12a and 12 b have the same shape and are arranged such that their shapescoincide with each other upon seeing from upward in the figure. However,in the present invention, the shape of the transparent electrode is notlimited to this.

For example, a holographic optical element is constructed such that apair of glass plates on which transparent electrodes are formed withstripes are arranged such that the respective transparent electrodestripes are crossed at right angle forming a grid shape upon seeing fromupward. With the construction, the light from the light source can bediffracted at any position where the transparent electrode stripes arecrossed upon seeing from upward. Accordingly, a dot can be displayed inthe field of the viewfinder corresponding to the position where thetransparent electrodes are crossed.

As described above, the viewfinder display using the holographic opticalelement with the above-described construction makes it possible todisplay given information in the field of the viewfinder with a dotmatrix.

For example, a holographic optical element is constructed such that atransparent electrode forming a figure and a letter or a grid shape isformed on one of a pair of glass plates and a uniform transparentelectrode is formed on the other glass plate.

The viewfinder display using the holographic optical element with theabove-described construction makes it possible to display giveninformation in the field of the viewfinder similar to the viewfinderdisplay using the above-described each holographic optical element.

In the holographic optical element 8 according to the above-describedfirst embodiment and that according to the variation, orientation of theliquid crystal and that of the ultraviolet-setting liquid crystal arethe same upon applying no-voltage. By varying the orientation of theliquid crystal upon applying voltage, difference between refractiveindex of the liquid crystal and that of ultraviolet-setting liquidcrystal is produced and the light is diffracted. In the presentinvention, the orientation of the liquid crystal is not limited to this.

A holographic optical element is constructed such that the orientationof the liquid crystal and that of the ultraviolet-setting liquid crystalare the same upon applying voltage, and upon applying no-voltage theorientation of the liquid crystal varies so that difference betweenrefractive index of the liquid crystal and that of theultraviolet-setting liquid crystal is produced resulting in diffractingthe light.

A viewfinder display using the holographic optical element with theabove-described construction makes it possible to display giveninformation in the field of the viewfinder similar to the viewfinderdisplay using the above-described each holographic optical element.

A fabrication method of the holographic optical element 8 according tothe above-described first embodiment is explained with reference toFIGS. 6A and 6B. FIGS. 6A and 6B are diagrams explaining a fabricationmethod of the holographic optical element according to the firstembodiment of the present invention.

At first, the above-described transparent electrodes Ha and 11 b areformed on each of a pair of glass plates 12 a and 12 b. The pair ofglass plates 12 a and 12 b are fixed in a state where the transparentelectrodes 11 a and 11 b are spaced and facing each other, and forms ahollow cell S.

Then, the hollow portion of the cell S is filled with a mixture 19composed of the above-described liquid crystal 13 and theultraviolet-setting liquid crystal 14. End portions of the cell in whichthe mixture 19 is filled are sealed by the sealant 15.

Then, a mask 20 having a striped openings is attached on the glass plate12 a of the cell S, and ultraviolet light is illuminated on the glassplate 12 a on which the mask 20 is attached (see FIG. 4A). Accordingly,the ultraviolet light is incident into the cell through the openings ofthe mask 20, and the ultraviolet-setting liquid crystal 14 ispolymerized where the ultraviolet light is incident. Therefore, theliquid crystal 13 and the ultraviolet-setting liquid crystal 14 areseparated in striped shape in the direction to the end of the cell, andthe orientation of the ultraviolet-setting liquid crystal 14 is fixed(see FIG. 4B).

With the above-described fabrication method, the holographic opticalelement 8 according to the first embodiment can be fabricated.Incidentally, the holographic optical element according to theabove-described variation can also be fabricated in the similar manner.

Another fabrication method of the holographic optical element isexplained with reference to FIGS. 7A and 7B. FIG. 7A is a schematicdiagram showing a device for fabricating the holographic optical elementwith another fabrication method.

In this fabrication method also, similar to the cell S used in theabove-described fabrication method, the cell S in which the mixture ofthe liquid crystal and the ultraviolet-setting liquid crystal is filledis used.

In FIGS. 7A and 7B, an ultraviolet laser beam emitted from a lightsource 21 is divided into two light beams La and Lb by a beam splitter22, and each beam is incident into each mirror 23 a or 23 b. The lightbeams La and Lb are reflected by respective mirrors 23 a and 23 b, andincident into respective beam expanders 24 a and 24 b. Here, the lightbeams La and Lb expand their beam diameters by the beam expanders 24 aand 24 b, respectively. The above-described cell S is arranged at acrossing position of the expanded light beams La and Lb. Accordingly,the light beams La and Lb are incident to the cell S from glass surfacesSa and Sb of the cell, respectively.

Here, the light beams La and Lb interfere to form a bright and darkstriped pattern, so that bright portions and dark portions are formed onthe cell S. Accordingly, the ultraviolet-setting liquid crystal ispolymerized at the bright portions. Thereby, the liquid crystal and theultraviolet-setting liquid crystal separate in a striped shape in thedirection to the end of the cell, and the orientation of theultraviolet-setting liquid crystal is fixed. Here, FIG. 7B is anenlarged view of the cell portion of FIG. 7A showing wave fronts ofbundles of rays La and Lb. In FIG. 7B, the crossing points whererespective wave fronts intersect are bright positions where theultraviolet-setting liquid crystal is polymerized.

With this fabrication method described above, the above-describedholographic optical element can be fabricated.

Second Embodiment

Then, a viewfinder display for compact camera according to the secondembodiment of the present invention is explained.

FIG. 8 is a schematic view showing a viewfinder display for a compactcamera according to a second embodiment of the present invention. InFIG. 8, a viewfinder display 25 for a compact camera is composed of aviewfinder objective lens 26, a holographic optical element 28 locatingat the imaging position of the viewfinder objective lens 26, and a lens27 for observing an object light from the viewfinder objective lens 26and given information from the holographic optical element 28. Moreover,the light source 9 for illuminating the holographic optical element 28,and the driver 10 for electrically controlling optical characteristic ofthe holographic optical element 28 are arranged. Here, the constructionof the holographic optical element 28 is the same as that of theholographic optical element according to the first embodiment excepttransparent electrodes 29 a and 29 b described later. Incidentally, thesame reference symbol is attached to the same portion as the firstembodiment and the duplicated explanations are omitted.

In the holographic optical element 28, transparent electrodes 29 a and29 b are arranged on each glass plate 12 a and 12 b forming L-shapes asshown in FIG. 9A. FIG. 9A is a view showing transparent electrodes 29 aand 29 b of a holographic optical element 28 according to the secondembodiment of the present invention. With this arrangement, an L-shapedline is displayed in the field of the viewfinder as a field frame. Thetransparent electrodes 29 a and 29 b are not limited to an L-shape, andit can naturally be used in combination with a transparent electrodewith a figure and a letter shape described in the first embodiment.

In this kind of viewfinder display 25 for a compact camera, the objectlight from the object passes through the viewfinder objective lens 26,the holographic optical element 28, and is observed by a photographerthrough the lens 27.

Then, the light emitted from the light source 9 is incident to theholographic optical element 28, and diffracted by the holographicoptical element 28 in the direction of the lens 27 (to the right in thefigure). The diffracted light is observed by the photographer as giveninformation through the lens 27.

With the construction described above, since given information (L-shapedfield frame) is displayed in the field of the viewfinder superimposingwith the above-described object image, the photographer can observegiven information together with the object image. An example ofinformation (field frame 29) displayed in the field of the viewfinder 17according to the present embodiment is shown in FIG. 9B. Here, FIG. 9Bis a view showing an example of information (field frame 29) displayedin the field of the viewfinder 17 according to the second embodiment.

In a compact camera, differing from a single-lens-reflex camera, aphotographic lens and a viewfinder are arranged separately with eachother. Accordingly, a displacement between the field of the viewfinder(whole area to be observed in the field of the viewfinder) and theshooting area (actual photographing area on the film) of thephotographic lens is produced in accordance with the distance from thecompact camera to the object, which is a so-called “parallax”.

With the construction described above, the viewfinder display for acompact camera according to the present embodiment makes it possible tocorrect the parallax by displaying a field frame in the field of theviewfinder indicating the shooting area in accordance with the shootingdistance (the distance from the compact camera to the object).

Moreover, the viewfinder display for a compact camera according to thepresent embodiment makes it possible to observe the shooting area of thephotographic lens indicated by the field frame in the field of theviewfinder together with the other area (the area that is notphotographed on the film). Accordingly, it is very effective forchoosing compositional arrangement upon displaying the shooting area inresponse to changing shooting mode such as a normal mode and a panoramicmode.

As described above, by using the holographic optical element constructedby the liquid crystal and the ultraviolet-setting liquid crystal, theviewfinder display for a compact camera according to the secondembodiment makes it possible to show various superimposed displays forvarious information with securing a bright viewfinder image as same asthe first embodiment.

The present invention makes it possible to provide a holographic opticalelement, a viewfinder display of a camera, and a camera that make itpossible to show various superimposed displays for various informationwith securing a bright viewfinder image.

1-4. (canceled)
 5. A viewfinder display of a camera displaying giveninformation superimposed with an object image, the viewfinder displayusing a holographic optical element, the holographic optical elementcomprising: a pair of spaced apart board-shaped transparent membersfacing each other; transparent electrodes formed on the respectivetransparent members and facing each other; an orientation-changeableliquid crystal; and an orientation-fixed liquid crystal; theorientation-changeable liquid crystal and the orientation-fixed liquidcrystal being arranged alternately with a striped shape between thetransparent members on which the transparent electrodes are formedfacing each other.
 6. The viewfinder display of a camera according toclaim 5, wherein the transparent electrodes are arranged on thetransparent members such that the transparent electrodes form a figureshape and a letter shape, and the figure and the letter are displayed asthe given information.
 7. The viewfinder display of a camera accordingto claim 5, wherein the transparent electrodes are arranged on thetransparent members such that the given information is displayed as adot-matrix.
 8. A viewfinder display of a camera displaying giveninformation superimposed with an object image, the viewfinder displayusing a combination of a plurality of holographic optical elements, eachholographic optical element comprising: a pair of spaced apartboard-shaped transparent members facing each other; transparentelectrodes formed on the respective transparent members and facing eachother; an orientation-changeable liquid crystal; and anorientation-fixed liquid crystal; the orientation-changeable liquidcrystal and the orientation-fixed liquid crystal being arrangedalternately with a striped shape between the transparent members onwhich the transparent electrodes are formed facing each other.
 9. Acamera arranging the viewfinder display of a camera according to claim 5in the vicinity of a screen.
 10. A camera arranging the viewfinderdisplay of a camera according to claim 8 in the vicinity of a screen.11. The viewfinder display of a camera according to claim 5, furthercomprising a light source that is arranged near a side of theholographic optical element and illuminates the holographic opticalelement from the side.
 12. The viewfinder display of a camera accordingto claim 11, wherein the light source illuminates the holographicoptical element entirely irrespective of whether voltage is applied tothe transparent electrodes.